The role of the Light Emitting Diode (LED) is expanding rapidly into automotive lighting applications. LEDs offer advantages in power consumption, useful life, size, and color choices. However, there are some challenges and problems in using LED light sources for automotive exterior lighting applications. These challenges include excess color shifts and intensity uniformity/variation when propagating in long optical elements such as light pipes and rings, thermal management, and associated packaging issues.
Color shifts may fail regulatory requirements and increase the LED piece price due to narrowed LED color-bin requirement. Poor thermal management shortens the LED life and can make the LED fail prematurely. Color shifts/non-uniformity and intensity non-uniformity can negatively impact the appearances of the lighting devices.
In current applications, the optical elements have extensions connecting the LEDs and the optical elements. The LED is placed in close proximity to an input end of the optical elements. In this case, the light travels along the extension section of the optical elements, resulting in light loss and unwanted color shifts. Multiple LEDs must be used and arranged in such a way that resolves the issues of color/intensity non-uniformity. However, this solution is more costly, difficult to package, and cannot be implemented in many applications.
Typically, light pipes have teeth cut on a back side of the pipe for directing light in a desired direction. These teeth are visible in the light pipe when the pipe is lit or unlit, which limits the styling features of the light pipes. Furthermore, in the existing technologies, the light travels along the pipe with undesirable effects such as decreasing intensity and color shifting, for example.
It would be desirable to have a lighting system and a method for providing a lighting pattern, wherein the lighting system and method minimizes non-uniform color and intensity in the lighting pattern, offers unique styling features, and provides design flexibility for the LED package and associated heatsinking devices.